Vibrio Fischeri Luminescence

My project is primarily focused on whether the adaptive radiation of various strains of V. fischeri from various ecological niches affects response to physiological stress. So far, I’ve been growing smooth morph and wrinkly spreader strains in various concentrations of sodium chloride. Growth has been evaluated using a spectrophotometer to estimate cell density in experimental cultures.

Recently, I have begun collecting data on the luminescence of the strains after they’ve grown for 24 hours in media with modified salinity. V. fischeri’s bioluminescence is crucial to the mutualism it shares with various species of squid; including E. scolopes. In this system, V. fischeri provide light utilized by the squid in counter-illumination. Light produced by V. fischeri helps to prevent silhouetting of the squid against the water surface in a form of camouflage. In return, the bacteria receive nutrients from the squid’s light organ. If bio-luminescence is affected by stress in the environment, there may be profound consequences for the host.

I have been able to collect data on luminescence using a luminometer. This procedure is similar to taking OD600 readings with a spectrophotometer and adds very little time to my experiments. Luminosity readings are highly variable as they are affected by the timing of when readings are taken relative to the bacteria’s growth phase as well various other factors. Therefore, it will be interesting to see if any kind of trend emerges along the salinity gradient.

Comments

This project sounds very interesting and I am curious to see what results you find from your luminescence readings. I do not know a ton about the differences between smooth morph and wrinkly spreader strains of V. fischeri, so I wondering, do you have any hypotheses of what variations there might be between the two strains?